Improvement in clocks



T. THOMPSON.

Clock.

Patented Jan. 25, 1870.

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THOMAS. TFIOMPSON, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO HIMSELF AND JOHN T. VIN SON, OF SAME PLACE.

Letters Patent No. 99,261, dated January 25, 1870.

IMPROVEMENT IN CLOCKS.

The Schedule referred to in these Letters Patent and making part of the same To all whom 'it may concern 7 Be it known that I, THOMAS THOMPSON, of London, England, now resident in \Vashiugtou, in the District of Columbia, have invented a new and useful Improvement in Clocks and I do hereby declare the following to be a full and'correctdescription of the same, suflicient to enableothers skilled in the art to which my invention appertaius, to fully understand and use the same,'reference being had to the accompanying drawings, which make part of this specification, and in which- Figure 1 is a front elevation, showing my improvement in clocks; and

Figures 2,and 3 are front and end views of the es capement-device, in different positions. I 7

Like letters of reference indicatelike parts in the several figures.

The nature of my invention consists First, in thearrangement and adjustment of the compeusation-rods,- between which the pendulum is suspended, in-such a manner. that the lowerend of the pendulum-rod, acted upon by the escapement-wheel,

. shall always be in the same distancefrom the latter,

as will be hereinafter explained.

Second, in the peculiarlocking and unlocking-device, whereby the'intermittent motion is given to the escape: ment-wheel.

A, in the drawings, represents the stand, to the lower end of which are secured the Working-parts of the clock-mechanism.

B B are two rods provided at their lowere'nds with screw-threads, and, securely held in nuts a, fastened to A. Their upper converging ends pass through guides 6;, and support a. small cross-rod, 0, provided with a head, D, ii-om which is suspended at short, straight spring, E, passing through a slot in a pin, 0, having pivoted to it the pendulum-rod '1, which is of the same length as' the rods B B, support-ing it, and carries the usual pendulum-weight G, made adjustable bya screwnut, (I, and an additional smaller weight, H, sliding freely on rod F, being held to the same by a small spring.

The compensation of the rods B Bis adjusted by means of the nuts to moving over the thread at the lower end of said rods, lengthening or shortening the rods, as the case may require. For instance,when.the parts are all put togethenaud the clock put in a furnace to test the expansion of the metals, it it should be found that the foot of the pendulum is drawn eni tirely out of the es'cnpement, it would beevident that rods'B B are too long; the remedy is found in lowering or shortening them, by running them down through the nuts a, the said nuts and guides I) serving to keep them at the proper angle. It will thus be seen, that before the clock is put in the market, its compensation is perfectly adjusted by the manufacturer, and a perfect time-piece furnished.

The endof rod F is tapered, as shown at c, and carries a short laterally-extending projection, f.

The point e is acted upon by the teeth of the esoapement-wheel I, while the projection or piece facts on a little dog, g, pivoted in the slotted head of a vertical rod, h, secured on a shaft 'i, which is pivoted between the name A and the arm j of a bracket, k, and carries another horizontal rod, 2, provided, at its outer end, with a small weight, m.

Between the arm j of the bracket 1c, and rod 71, the

shaft'i has a small place out out, leaving a square surface, as shown at n, which is horizontal, at which position therod h is vertical, as shownin figs. 1 and 3. Che of the lower teeth of the escapement-wheel I rests against the edge of this place 01-, without being able to pass it, but when this place n, on shaft '5, is in position, as shown in fig. 2, the tooth which rested against the edge of place it can pass the latter.

The dog gis provided with a little weight at its lower end, suiiieient to keep it in a vertical position when not acted. upon.

Motion is imparted to the escapement-wheel I through wheels J K L, by means of the weight M, which is attached to a cord, N, passing over a pulley, O, aud is wound on a drum, P, on the shaft of wheel L. The I drum 1, as the cord uuwinds, transmits its motion to the wheel L, by means of the ratchet 12 and pawl 0.

As the pendulum is started from left to right, its point e strikes the little dog g, carrying with it the rod h, and thus turning the shaft 1', in such a manner that the tooth of escapement-wheel I, then resting against place 11, passes it. At this moment the point e of the pendulum, has passed over dog g, and the weight on, on rod 1, turns shaft i, sotha-t rod h is again vertical, and that the tooth of escapemeutwheel I, next to the one that has just passed the place a, will now rest against the latter. As the tooth passes the place 11-, the second tooth above it, in the line of motion of the escapcment-wheel I, engages with the point e of the pendulum, giving it an impetus. On

its return motion, the point e of the pendulum passes over dog g, which, being pivoted, bends down to allow the point e to pass, without operating the rod h, and as soouas point c has passed it, it is returned to its normal position, by the little weight at its end.

A great advantage of having the impetus given to the pendulum-rod itself, and at its lower end, is that it requires less power to give the impetus, and that the pendulum-rod may be shorter. But to enable this arrangement to beinade, provision must be made for the compensation for the expansion of the pendulumrod, for, were it the least little bit too short, it would not be acted upon and were .it too long, it would look the escapement-wheel. I accomplish this by the suspension of the pendulum-rod between and from the compensating-rods B B, so that the downward expansion of the pendulum-rod is counteracted by their upward expansion. The lower end of the pendulum-rod must, consequently-,be continually in the same certain position relative to the teeth of the escapernent-wheel.

As the necessity of force for'the impetus is decreased by my above-described arrangement, the locking and unlocking-device for the escapement-wheel requires also less power, and I am hereby enabled to materially simplify it, for it will be easily seen, that the above described device for this purpose is very much simpler and much less liable to disorder than the common spring-device now in use. 4

As the pendulum-rod F expands downwardly, this expansion is equalized by the upward expansion of the rods 15. But this equalization does not compensate for the irrr-gularityof motion caused by the-lengthening itself of the pendulum-rod, for the longer the pendulumrod, the slower its motion. To periectly compensate for this lengthening of the pendulum-rod, I suspend the same by the spring E, which. has its real workingfulcrum atthe lower endof the slot of pin 0, in which it is held. As the upward elongation of rods B equalizes the downward elongation of rod F, the spring E, being drawn through the slot of pin 0, upwardly, becomes shortened, and, consequently, stronger, ivin'g quicker motion to the pendulum-rod, and thus compensating for the slower motion of the rod, caused by its elongation. \Vith, the contraction of the several parts, the reverse action takes place. By this means I obtain a perfect compensation for all effects of temperature. I

Having thus described my invention,

What I claim as new therein, and desire to secure by Letters Patent,iis

1., The arrangement of the compensating-rods B B, holding the pendulum-rod suspended between them, so that the lower end of the pendulum-rod is always at the same distance from the teeth of the escape- 

